GOODWILL AND LONG-LIVED ASSETS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
GOODWILL AND LONG-LIVED ASSETS [Abstract]
Impairment of long-lived assets	$ 0	$ 0
Changes in carrying amount of goodwill [Abstract]
Gross Goodwill Balance		115,872	$ 108,417	$ 108,417	$ 115,872
Accumulated Impairment Losses		(93,665)	(93,881)	(93,881)	(93,665)
Net Goodwill Balance		22,207	14,536	$ 14,536	$ 22,207
Goodwill impairment	0	0
Finite-Lived Intangible Assets [Line Items]
Amortization	100	100
Net carrying amount	44
Intangible Assets (Excluding Goodwill) [Abstract]
Gross carrying amount, Total	470
Adjustments	0
Gross carrying amount, Total	470
Accumulated amortization, Total	420
Amortization	6
Accumulated amortization, Total	426
Net carrying amount			44
Amortization of intangible assets	100	$ 100
Estimated future amortization expense [Abstract]
Remainder of 2016			12
2017			16
2018			16
Total	44		44
Trade Name [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, beginning balance	310
Adjustments	0
Gross carrying amount, ending balance	310
Accumulated amortization, beginning balance	308
Amortization	2
Accumulated amortization, ending balance	310
Net carrying amount	$ 0
Weighted average amortization period	7 years
Intangible Assets (Excluding Goodwill) [Abstract]
Amortization of intangible assets	$ 2
Estimated future amortization expense [Abstract]
Total	0		0
Curriculum [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, beginning balance	160
Adjustments	0
Gross carrying amount, ending balance	160
Accumulated amortization, beginning balance	112
Amortization	4
Accumulated amortization, ending balance	116
Net carrying amount	$ 44
Weighted average amortization period	10 years
Intangible Assets (Excluding Goodwill) [Abstract]
Amortization of intangible assets	$ 4
Estimated future amortization expense [Abstract]
Total	$ 44		$ 44